CEP Air Quality & Atmospheric Science Flashcards

Which U.S. federal law establishes the primary framework for regulating outdoor air quality and sets National Ambient Air Quality Standards (NAAQS)?

Answer: Clean Air Act

The Clean Air Act (CAA), originally passed in 1963 and significantly amended in 1970 and 1990, is the primary federal law governing air quality and authorizes the EPA to set NAAQS.

A 'criteria air pollutant' regulated under NAAQS includes which of the following?

Answer: Particulate Matter (PM2.5)

PM2.5 is one of six criteria air pollutants regulated under NAAQS; the others are ozone, CO, NO2, SO2, and lead.

What is the primary difference between a 'primary' and 'secondary' NAAQS standard?

Answer: Primary standards protect public health; secondary standards protect public welfare

Primary NAAQS are designed to protect public health (including sensitive populations), while secondary standards protect public welfare such as crops, vegetation, and visibility.

Which air quality modeling approach is most commonly used by EPA for dispersion modeling of industrial stack emissions?

Answer: AERMOD

AERMOD (AMS/EPA Regulatory Model) is EPA's preferred steady-state Gaussian plume model for near-field dispersion of air pollutant emissions from stationary sources.

Under the Clean Air Act, a 'nonattainment area' is defined as a region where:

Answer: Ambient air quality exceeds one or more NAAQS

A nonattainment area is a geographic area that does not meet (or 'attain') one or more of the NAAQS for criteria air pollutants.

The term 'fugitive emissions' in air quality management refers to:

Answer: Emissions not released through a stack, vent, or other confined flow

Fugitive emissions are pollutants that escape into the atmosphere without passing through a control device or defined exhaust point, such as dust from unpaved roads or leaks from equipment.